Production of beneficiated iron ore-coked product



United States Patent 3,350,195 PRODUCTION OF BENEFICIATED IRON ORE-COKED PRODUCT King L. Mills, Bartlesville, Okla., assignor to Phillips Petroleum Company, a corporation of Delaware Filed Aug. 20, 1965, Ser. No. 481,310 6 Claims. (Cl. 75-1) ABSTRACT OF THE DISCLOSURE Beneficiated iron ore is produced by coking a heavy hydrocarbon material in admixture with iron ore, subjecting the resulting coked matrix in admixture with H O to partial oxidation with an O -containing gas at elevated temperature to form CO and H and treating said matrix prior to oxidation under reducing conditions with the produced CO and H to partially reduce the iron ore in said matrix.

This invention relates to a process for producing a beneficiated iron ore-coke material for smelting to produce metallic iron.

The conventional method for the production of iron comprises mixing iron ore, limestone, and metallurgical coke and feeding the mixture to the top of a blast furnace. Molten iron and slag are separately recovered from the bottom of the furnace. The metallurgical coke employed is of high strength so as to support the charge Without crushing and thus bed for blasting.

Iron ore deposits exist in proximity to petroleum fields but remote from coal deposits which might provide coke for the manufacture of iron.

This invention is concerned with a method or process for utilizing petroleum residues and heavy coke-forming hydrocarbons in preparing beneficiated iron ore for smelting.

Accordingly, it is an object of the invention to provide a process for producing a beneficiated iron ore-coke material, which may also contain lime, for use in smelting to produce pig iron. Another object is to provide a process for making such beneficiated iron ore-coke material utilizing relatively cheap heavy hydrocarbon residues having coking properties. Other objects of the invention will become apparent to one skilled in the art upon consideration of the accompanying disclosure.

A broad aspect of the invention comprises admixing iron ore and heavy cokable hydrocarbon material under coking conditions to form a coked matrix containing the iron ore, thereafter subjecting the coked matrix to partial oxidation by contacting the matrix under oxidizing conditions with an O -containing gas at a temperature in the range of 1000 to 2000 F. to form CO and H treating the matrix prior to oxidation with resulting CO and H under reducing conditions to partially reduce the iron ore; and recovering and cooling the beneficiated product. Lime may be added to the iron ore-hydrocarbon material during coking so as to incorporate sufiicient lime in the matrix for fiuxing during smelting. It is advantageous to recover unreacted CO and H from the reducing gases and recycle these to the reducing step. The process produces valuable hydrocarbon materials in the coking step which are recovered as products of the process.

A more complete understanding of the invention may be had by reference to the accompanying schematic drawing which is a flow sheet illustrating a preferred embodiment of the invention.

The readily cokable hydrocarbon material (residuum, tar, pitch, asphaltenes, asphalt, etc.) is fed into coker via line 12 after passing thru furnace 14 which heats the give suflicient porosity to the reaction hydrocarbon material to a temperature in the range of 800 to 1000 F. and sufiicient for coking. Simultaneously with the feeding of the hydrocarbon material into coker 10, iron ore is gravitated onto the coking hydrocarbon material by passing same thru lines 16 and 18 onto a distributing means 20 which showers the iron ore onto the coking material to break gas bubbles and foam therein as the coked material builds up. Lime may also be introduced into the coker with the iron ore thru line 22. This operation is continued until the level of coke, ore, and lime builds up to a predetermined fixed leyel and operation is terminated to permit removal of the coked matrix from the coker. Coker distillates formed in coker 10, including valuable hydrocarbons, are withdrawn from the upper section of the coker thru line 23 and processed for recovery of the hydrocarbons.

Coker 10 is preferably a hearth-type coker (Knowles oven). A hard, dense coke of less than 20 percent volatile matter (at 1600 F.) is formed containing from 6 to 50 pounds of iron ore per pound of coke and, when lime is added, an amount of lime in the range of about 0.2 to 0.25 pound of lime per pound of iron ore.

The hard coked matrix containing the iron ore, with or without lime, is removed from the coker by conventional means such as with Water jets or drills.

The chunks or particles of coke-iron ore matrix are passed thru an upright treating zone in which oxidation of coke is effected in the lower section and reduction of iron ore in the upper section. The coked matrix recovered from coker 10 thru line 24 is passed into upright tower 26 thru line 28. The coked matrix containing iron ore is subjected to partial oxidation with air or other O -containing gas introduced thru line 30 of the lower section of tower 26. The flow of air is controlled so as to oxidize sufiicient coke in the lower section of the tower to produce the desired temperature in the range of 1000 to 2000 F. This partial oxidation of coke produces CO and H which effect partial reduction of the iron ore in the coke matrix as it passes thru the upper section of the tower 26 which is a reducing section.

The oifgas from tower 26 is passed thru line 32 into conventional gas separation means 34 which separates the offgas into light hydrocarbon gases recovered thru line 36, H and CO recovered thru line 38, any suitable portion being recycled to the upper section of tower 26 thru line 40, and N and CO being removed thru line 42. Where desired, H and CO not recycled are recovered thru line 44. The partially reduced iron ore-coke matrix, which may also contain lime, is withdrawn from the bottom of tower 26 via line 46.

Additional information on upgrading or beneficiating iron ore utilizing heavy hydrocarbon materials for the coking feature is disclosed in US. Patents 3,072,474 and 3,097,156.

To illustrate the invention, 1000 pounds of residuum is heated to a temperature in the range of 8001000 F. and is fed into coker 10 thru line 12. Simultaneously, 2300 pounds of particulate iron ore (Fe O is dispersed onto the mass of coking material to form 250 pounds of coke admixed with the iron ore. About 750 pounds of gas and distillates are produced in line 23.

The coke-iron ore mass is broken up and removed from the coker and gravitated thru tower 26 where it is contacted with about 1450 pounds of air under combustion temperatures of about 1800 F. to partially reduce the ore, 2000 pounds of Fe O being recovered thru line 46 substantially free of coke. When substantial quantities of coke are desired in the partially reduced ore, additional residuum or a lesser amount of ore is fed to the coker. Off gas from tower 26 amounts to 2100 pounds.

Steam may be substituted for or admixed with the air in line 30. 7

Certain modifications of the invention will become apparent to those skilled in the art and the illustrative details disclosed are not to be construed as imposing unnecessary limitations on the invention.

I claim:

1. A process for beneficiating iron ore which comprises the steps of:

(1) admixing iron ore and heavy cokable hydrocarbon material under coking conditions to form a coked matrix containing from 6 to 50 pounds of iron ore per pound of coke, said coke containing less than 20 percent volatile matter;

(2) gravitating the resulting coke-iron ore matrix of step (1) thru an upright treating tower;

(3) contacting said matrix in admixture with H O in the lower section of said tower with an ascending stream of O -containing gas at a temperature in the range of 1000 to 2000" F. to partially oxidize the coke in said matrix and form C and H (4) passing the resulting gas from step (3) containing CO and H upwardly thru said matrix in the upper section of said tower to partially reduce the iron ore therein; and

(5) recovering, and cooling the resulting beneficiated iron ore from the foregoing steps.

2. A process for producing beneficiated partially reduced iron ore fixed in a coke matrix which comprises the steps of:

(1) heating a readily cokable heavy hydrocarbon material to a coking temperature;

(2) passing the hot material from step (1) into a cok- I ing zone and maintaining coking conditions therein so as to gradually build up a mass of coke therein; (3) simultaneously with step (2), feeding particulate iron ore into an upper section of said coking zone so that said ore gravitates onto the growing mass of coking material;

(4) breaking up the resulting mixture of coke and iron ore and removing same from said coking zone;

(5) gravitating the particulate coke-iron ore from step (4) thru an upright oxidation zone countercurrently to an ascending stream of O -containing gas in admixture with H O so as to burn a portion of said coke, maintain a temperature therein in the range of 1000 to 2000 F., from C0 and H and partially reduce said iron ore; and

(6) recovering and cooling the beneficiated coke-iron ore from step (5).

3. The process of claim 2 wherein the proportions of iron ore and hydrocarbon material are regulated so as to produce in steps (2) and (3) a coke of less than 20 percent volatile matter containing iron ore in the range of 6 to pounds per pound of coke.

4. The process of claim 3 wherein the O -containing gas in step (5) is air.

5. The process of claim 1 wherein lime in fluxing quantity is admixed with the coke-iron ore in step (1).

6. The process of claim 1 wherein H and C0 are recovered from the overhead gas from step (4) and recycled to step (4).

References Cited UNITED STATES PATENTS 1,488,386 3/1924 Girouard et a1. -4 1,848,710 3/1932 Gustafsson 75-3 2,397,993 4/ 1946 Urquhart 754 2,676,095 4/1954 De Vaney et a1 753 2,794,728 6/ 1957 Lesher 754 35 2,812,249 11/1957 Culberson et al. 75-4 BENJAMIN HENKIN, Primary Examiner. 

1. A PROCESS FOR BENEFICIATING IRON ORE WHICH COMPRISES THE STEPS OF: (1) ADMIXING IRON ORE AND HEAVY COKABLE HYDROCARBON MATERIAL UNDER COKING CONDITIONS TO FORM A COKED MATRIX CONTAINING FROM 6 TO 50 POUNDS OF IRON ORE PER POUND OF COKE, SAID COKE CONTAINING LESS THAN 20 PERCENT VOLATILE MATTER; (2) GRAVITATING THE RESULTING COKE-IRON ORE MATRIX OF STEP (1) THRU AN UPRIGHT TREATING LOWER; (3) CONTACTING SAID MATRIX IN ADMIXTURE WITH H2O IN THE LOWER SECTION OF SAID TOWER WITH AN ASCENDING STREAM OF O2-CONTAINING GAS AT A TEMPERATURE IN THE RANGE OF 1000* TO 2000*F. TO PARTIALLY OXIDIZE THE COKE IN SAID MATRIX AND FORM CO AND H2; (4) PASSING THE RESULTING GAS FROM STEP (3) CONTAINING CO AND H2 UPWARDLY THRU SAID MATRIX IN THE UPPER SECTION OF SAID TOWER TO PARTIALLY REDUCE THE IRON ORE THEREIN; AND (5) RECOVERING, AND COOLING THE RESULTING BENEFICIATED IRON ORE FROM THE FOREGOING STEPS. 